From the Guidelines
Taking 10,000 IU per day of vitamin D is not recommended for routine supplementation and could potentially lead to toxicity with long-term use, as it exceeds the recommended daily allowance and upper limit considered safe for most people. The recommended daily allowance for most adults is 600-800 IU, with an upper limit of 4000 IU per day considered safe for most people 1. Vitamin D toxicity, while rare, typically occurs at sustained daily doses above 10,000 IU, leading to elevated calcium levels in the blood (hypercalcemia) 1. This can cause symptoms like nausea, vomiting, weakness, frequent urination, kidney problems, and in severe cases, heart rhythm abnormalities.
Some key points to consider:
- Vitamin D is fat-soluble, meaning it's stored in body tissues and not easily excreted, so excessive amounts can accumulate over time 1.
- High doses of vitamin D, such as 10,000 IU per day, have been used in specific medical conditions, such as advanced chronic kidney disease (CKD), without evidence of toxicity, but this should be done under medical supervision 1.
- The safer vitamin D sterol may be ergocalciferol rather than cholecalciferol, although there are no controlled comparisons of cholecalciferol and ergocalciferol in humans 1.
- If you're considering high-dose vitamin D, it's essential to do so only under medical supervision with periodic blood tests to monitor your vitamin D and calcium levels 1.
In terms of morbidity, mortality, and quality of life, it's crucial to prioritize caution when considering high-dose vitamin D supplementation, as excessive intake can lead to severe health complications. Therefore, it's recommended to adhere to the established daily allowance and upper limit for vitamin D intake, unless otherwise advised by a healthcare provider based on individual health needs and blood test results.
From the FDA Drug Label
Contraindicated in people with hypercalcemia, malabsorption syndrome, abnormal sensitivity to the toxic effects of vitamin D, and hypervitaminosis D. Warning In case of accidental overdose contact a doctor or poison control center immediately. The FDA drug label does not answer the question.
From the Research
Vitamin D Toxicity
- The risk of toxicity from daily ingestion of 10,000 International Units (IU) of vitamin D has been studied in several research papers 2, 3, 4, 5, 6.
- According to a study published in 2020, daily doses of up to 10,000 IU of vitamin D were found to be safe and well-tolerated in healthy adults, with no significant differences in adverse events between treatment arms 3.
- Another study from 2007 suggests that the threshold for vitamin D toxicity has not been established, but hypercalcemia is the hazard criterion for vitamin D, and daily doses of up to 10,000 IU are likely to pose no risk of adverse health effects to almost all individuals in the general population 4.
- A 2009 study also supports the idea that daily ingestion of 10,000 IU of vitamin D is safe, as it is equivalent to the amount of vitamin D produced by brief, suberythemal exposure to ultraviolet light, and plasma 25-hydroxyvitamin D concentrations can reach up to 220 nmol/L (88 ng/mL) without causing toxicity 6.
- However, a 2023 systematic review and meta-analysis found that daily supplementation with 3200-4000 IU of vitamin D may increase the risk of hypercalcemia and other adverse events in a small proportion of individuals, indicating that this dose is not completely safe 5.
Key Findings
- Daily doses of up to 10,000 IU of vitamin D are generally considered safe and well-tolerated in healthy adults 3, 4, 6.
- Hypercalcemia is the primary hazard criterion for vitamin D toxicity, and daily doses of up to 10,000 IU are unlikely to cause hypercalcemia in most individuals 3, 4.
- The risk of adverse events, including hypercalcemia, may be higher with daily doses of 3200-4000 IU of vitamin D, particularly in certain populations 5.